Houston: The death toll in the massive fertilizer plant explosion in Texas has risen to 14, with US investigators announcing they had nearly finished search and rescue efforts.

Two days after the West Fertilizer Company fertilizer facility exploded in the US town of West, Texas, the residents were grappling with the tragedy. "It's going to be a long recovery for this community," Governor Rick Perry told reporters on Friday. The death toll rose to 14, which included the city secretary, who was also on the city of West's 29-member volunteer fire department, said Mayor Tommy Muska, also a volunteer firefighter.

In total, five West firefighters died battling the blaze, along with one Dallas firefighter and four emergency responders, the State Firemen's and Fire Marshals' Association of Texas said on Thursday. "It's devastating. I've been a member of the firefighters for 26 years," Muska said. "These guys are my friends."

The explosion tore through the roof of West Fertilizer Company, charring much of the structure and sending massive flames into the air late Wednesday night. President Barack Obama issued an emergency declaration and pledged federal disaster relief aid to help West recover. The explosion caused a 2.1-magnitude earthquake. It also destroyed many homes in the small town of 2,800. Many, including Muska, were staying in hotels or with friends.

The destruction made it hard to account for exactly how many people had been displaced, McLennan County Judge Scott Felton said on Friday. He estimated that 99 per cent of people originally thought to be missing had been accounted for. "This is still being treated as a crime scene," he said.

The fertilizer plant explosion leveled buildings, ripped up walls and threw people on the ground blocks away. About half the town was evacuated, including a nursing home with 133 residents. It was still unclear what the exact number of casualties was.

Federal and state investigators were awaiting clearance to enter the blast area to search for clues to the cause of both the initial fire and explosions. "It's still too hot to get in there," Federal Bureau of Alcohol, Tobacco, Firearms and Explosives spokeswoman Franceska Perot said.

There was no indication of foul play. With destruction so vast, it was well into Thursday before officials could comprehend and then describe the scope of the tragedy. While the cause of the blast is not clear, ammonium nitrate used in many such farm applications is explosive and often used to build deadly roadside bombs in Afghanistan.